Anatomic Changes in the Macroscopic Morphology and Microarchitecture of Denervated Long Bone Tissue after Spinal Cord Injury in Rats

Abstract

To study the effects of mechanical loading on bones after SCI, we assessed macro- and microscopic anatomy in rats submitted to passive standing (PS) and electrical stimulation (ES). The study design was based on two main groups of juvenile male Wistar rats with SCI: one was followed for 33 days with therapies starting at day 3 and the other was followed for 63 days with therapies starting at day 33. Both groups were composed of four subgroups (n = 10/group): (1) Sham, (2) SCI, (3) SCI + PS, and (4) SCI + ES. Rehabilitation protocol consisted of a 20-minute session, 3x/wk for 30 days. The animals were sequentially weighed and euthanized. The femur and tibia were assessed macroscopically and microscopically by scanning electronic microscopy (SEM). The SCI rats gained less weight than Sham-operated animals. Significant reduction of bone mass and periosteal radii was observed in the SCI rats, whereas PS and ES efficiently improved the macroscopic parameters. The SEM images showed less and thin trabecular bone in SCI rats. PS and ES efficiently ameliorated the bone microarchitecture deterioration by thickening and increasing the trabeculae. Based on the detrimental changes in bone tissue following SCI, the mechanical loading through weight bearing and muscle contraction may decrease the bone loss and restore the macro- and microanatomy.

The effect of peripheral nervous system in growing bone biomechanics. An experimental study

“…Later in 1997 Edoff et al 15 concluded that after dissection of the sciatic and the saphenous nerve, the length of metatarsal bones in immature rats was shorter compared to the normal ones. 17 years later, Zamarioli et al 18 concluded that after provoking spinal cord injury, both macroscopic as well as microscopic structures of the bone are altered.…”

A Primary Care Provider's Guide to Bone Health in Spinal Cord-Related Paralysis

“…Bone loss after neurologic injury is postulated to be multifactorial: severe immobilization and loss of weight loading related to paralysis, 4,5 sensory and sympathetic denervation of the bone, 6,7 loss of anabolic factors (ie, testosterone, growth hormone), 8 presence of catabolic factors (systemic inflammation, administration of drugs like steroids at the time of injury), 9 other factors locally influencing bone metabolism (ie, paracrine influences from atrophied muscles), 10 and chronic administration of drugs known to negatively affect bone metabolism (antidepressants, anticonvulsivants, opioids, proton pump inhibitors, anticoagulants). 11 Bone loss is dependent on time from and extent of neurologic injury, with most bone loss occurring in the first year after complete motor paralysis.…”

Effect of Electrical Stimulation and Vibration Therapy on Skeletal Muscle Trophism in Rats with Complete Spinal Cord Injury

“…23 Although frequencies ranging from 20 to 70 Hz are recommended to ensure participant safety, 24 Hadi et al 25 demonstrated previously that subjects with SCI preferred high-frequency vibration.…”

“…Thus, the authors believe that ES should be included in the rehabilitative program of SCI individuals to improve muscle health and also bone quality, because of osteogenic effects of muscle contraction on the bone tissue. 15,23,36,37 …”